Sono riuscito a farlo utilizzando KeyRemap4MacBook.
Questa è la parte di personal.xml, se qualcuno ne ha bisogno:
<item>
<name>Windows-style AltGr mappings</name>
<identifier>remap.altgr</identifier>
<autogen>--KeyToKey-- KeyCode::V, ModifierFlag::OPTION_R, KeyCode::KEY_2, ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L</autogen>
<autogen>--KeyToKey-- KeyCode::F, ModifierFlag::OPTION_R, KeyCode::BRACKET_LEFT, ModifierFlag::OPTION_L</autogen>
<autogen>--KeyToKey-- KeyCode::G, ModifierFlag::OPTION_R, KeyCode::BRACKET_RIGHT, ModifierFlag::OPTION_L</autogen>
<autogen>--KeyToKey-- KeyCode::B, ModifierFlag::OPTION_R, KeyCode::BRACKET_LEFT, ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L</autogen>
<autogen>--KeyToKey-- KeyCode::N, ModifierFlag::OPTION_R, KeyCode::BRACKET_RIGHT, ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L</autogen>
<autogen>--KeyToKey-- KeyCode::W, ModifierFlag::OPTION_R, KeyCode::BACKSLASH, ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L</autogen>
<autogen>--KeyToKey-- KeyCode::Q, ModifierFlag::OPTION_R, KeyCode::BACKSLASH, ModifierFlag::OPTION_L</autogen>
</item>